wp admin image column

gistfile1.txt

<?php

// column post image
function add_thumb_column($cols) {
    $cols['thumbnail'] = 'Image';
    return $cols;
}
function add_thumb_value($column_name, $post_id) {
        
        $width = (int) 120;
        $height = (int) 120;
        
        if ( $column_name == 'thumbnail' ) {
            
            // thumbnail
            $thumbnail_id = get_post_meta( $post_id, '_thumbnail_id', true );

            // image from gallery
            $attachments = get_children( array('post_parent' => $post_id, 'post_type' => 'attachment', 'post_mime_type' => 'image') );

            if ($thumbnail_id) {
                $thumb = wp_get_attachment_image( $thumbnail_id, array($width, $height), true );
            } elseif ($attachments) {
                foreach ( $attachments as $attachment_id => $attachment ) {
                    $thumb = wp_get_attachment_image( $attachment_id, array($width, $height), true );
                }
            }
            if ( isset($thumb) && $thumb ) {
                echo edit_post_link($thumb);
            } else {
                echo '-';
            }
        }
}
// for posts
add_filter( 'manage_posts_columns', 'add_thumb_column' );
add_action( 'manage_posts_custom_column', 'add_thumb_value', 10, 2 );
// for pages
add_filter( 'manage_pages_columns', 'add_thumb_column' );
add_action( 'manage_pages_custom_column', 'add_thumb_value', 10, 2 );